Spacer for dies

ABSTRACT

A die holder and spacer including a first cylindrical portion equipped with an inside recess and a solid base and a second cylindrical portion that is at least partially solid and is attached to the solid base of and outside the first portion, said portions being coaxial. In a variant, an elastic damping device is attached to the inside of the inside recess and protrudes therefrom, and a cup element is placed outside and above the elastic device and outside the first cylindrical portion; the cup element is provided with a ring-shaped edge firmly secured to a corresponding ring-shaped portion of the solid base of the first cylindrical portion. The first and second cylindrical portions are made as a single part by a thermoplastic-material injection process. In an improved embodiment, the material includes semi-crystaline polyamides or polymers and preferably includes fiberglass reinforcement.

This invention refers to a device for protecting dies or the machines on which the dies are mounted at times when the dies are not being used.

In the field of machines which use dies or on which dies are mounted, it is a known fact that when the dies are not being used, they may be a source of some typical problems involving either safety, the integrity of the dies, or even the machines.

In FIG. 1, stamping machine 100 is shown, with item 101 indicating the lower portion of the die or column and item 102 indicating the upper portion, which we shall refer to as the “die”; when machine 100 is inactive, said items 101 and 102 are separated from each other by a certain distance “t”.

-   -   An initial cause of safety problems is the fact that, when the         machine is not active, said dies 101 and said columns 102, which         oppose each other and should be safely secured, can         inadvertently come closer to each other and even close during         maintenance; if an operator's hand is accidentally placed         between these items, there is obviously a real risk that the         operator's hand will be trapped and crushed;     -   A second cause of problems has to do with the fact that when the         machine or just the assemblies consisting of a die and its         column are being moved, these items can come loose or vibrate or         may come into potentially hazardous contact with each other; not         only can these items splatter shards outward, in which case they         will surely be damaged, there will also be an inevitable         economic loss given their generally high cost;     -   A third possibility results from the fact that, when the machine         is inactive, said die and column items must be kept at a certain         precise distance for various technical reasons, such as for         calibrating the machine.

In order to overcome these drawbacks, solid or partially blocks 104 are normally made and used, as seen in FIG. 2, and are simply placed between the die and its column so as to occupy said distance “t” and thus block said items at a preset distance.

In particular, when the shape of said items, i.e. the die and column, is cylindrical, said solid blocks 103 may be similarly shaped like cylindrical bushings which match both said items 101 and 102.

This very empirical solution, however, has some drawbacks which are specifically:

-   -   first and foremost, blocks 103 are made by turning metal rods;         turning work is normally known to be costly and therefore not         very efficient at making parts serving a very simple purpose,         such as that of a “shim”;     -   in addition, said blocks 103 have the same diameter and         therefore cannot be securely adapted to parts with different         diameters, given that they can slip laterally for any reason         whatsoever;     -   thirdly, said blocks are rigid and therefore do not allow for         even the slightest movement between the die and column, which,         due to an obvious reaction, causes an undesirable mechanical         stress between the components of the machine on which said dies         and corresponding columns are mounted.

It would therefore be desirable to make a die spacer that can substantially limit the above drawbacks, which is the main purpose of this invention.

This purpose, along with other purposes which will be more clearly specified below, are achieved by a die spacer made and operating according to the enclosed claims.

The features and advantages of the invention will become clear from the following description, given as a non-limiting example, in reference to the enclosed drawings in which:

FIG. 1 shows a schematic side view of one die according to the prior art, which can use the present invention,

FIG. 2 shows the die of FIG. 1, to which a spacer according to the prior art has been added,

FIGS. 3 and 4 show perspective views from two different observation points, respectively, of a spacer according to the invention,

FIG. 5 shows the die of FIG. 1, to which a spacer according to the prior art has been added,

FIGS. 6A and 6B show partial transparencies of a schematic starting condition and a working condition, respectively, of a spacer according to the invention,

FIGS. 7A and 7B show two flat vertical middle cross-sections of two corresponding installation and operation examples of a spacer according to the invention,

FIG. 8 shows an exploded view of an improved variant of the spacer according to the invention,

FIG. 8A shows the spacer of FIG. 8 in an “exploded” view, but with a flat middle cross-section passing through center axis “X” of the spacer in FIG. 8,

FIG. 8B shows a middle cross-section of the spacer of the previous figure in the finished condition ready for use,

FIGS. 9A and 9B show two perspective views from two different observation points of an improved accessory of a spacer according to the invention,

FIG. 9C shows a perspective view of the accessory in FIGS. 9A and 9B after the accessory has been mounted on a spacer according to the invention,

FIGS. 10A, 10B, and 10C show perspective views of three subsequent operating states of the accessory in FIGS. 9A, 9B, and 9C, respectively (FIG. 10B shows an intermediate transition position),

FIGS. 11A and 118 show perspective and schematic views, respectively, of the spacer in FIGS. 10A and 10C.

In reference to FIGS. 3, 4, and 5, an improved spacer according to the invention consists of a single body that comprises two cylindrical portions firmly connected to each other by means of a corresponding base, in which in particular:

-   -   a first cylindrical portion 1 has an internal cylindrical recess         2 open to the outside at one base, the opposite base 3 of which         is solid,     -   a second cylindrical portion 4, at least partially solid, firmly         connected to the outside of solid base 3 of first portion 1.         As shown in the figures, inside diameter “D” of first portion 1         is greater than outside diameter “d” of second portion 4.

This feature is clarified by observing FIGS. 6A, 6B, and 7A, 7B; indeed, if die 102 is to be spaced safely from corresponding column 101, a portion of the spacer needs to be able to be coupled to the corresponding item without any risk of slipping out or being ejected; this goal is achieved if one of said cylindrical portions can be engaged by dovetailing like a cap on the outer surface of the other item to be spaced away.

But this condition is normally achievable if the portion that caps the corresponding item (die or column) has a recess with substantially the same dimensions so as to easily fit with said item, be it a die or column.

Consequently, since said recess is defined by a cylindrical wall and said wall obviously cannot have a zero thickness, and (see FIGS. 6A, 6B) since said cylindrical portion 4 is inserted into inside cylindrical part 101A of column 101, which normally has the same width as die 102, outside diameter “D” of first hollow portion 1 is necessarily greater than outside diameter “d” of second cylindrical portion 4.

In addition, as can be seen in these same figures, and for obvious design and functional reasons, it is also appropriate for said first and second cylindrical portions 1 and 4 and said inside recess 2 to be coaxial with respect to the same axis “X”.

The main solution just described allows for numerous beneficial improvements which solve some problems which may remain unsolved by the invention described above.

One of these problems consists of the fact that, even though said spacer improves the technique for protecting dies, it may be that said dies, although joined to each other, need to be connected in a non-rigid way so as not to subject the rest of the machine to excessive streeses.

To overcome this drawback, said internal recess 2, in reference to FIGS. 8, 8A, and 8B, can be used to insert an elastic damping means 5, particularly a cylindrical damper made of elastomeric material, which protrudes from the outer edge of said recess 2 by length “s”.

A cylindrical cup element 6, which is therefore hollow, is placed above the assembly consisting of said elastic means 5 and said first portion 1, arranged outside and above said elastic means 5 and outside said first cylindrical portion 1.

In practice, an expert skilled in the art will understand that a shock-absorbing or damping element which can elastically absorb impacts or any vibrations between the die and the corresponding column, is thus made.

In addition, said cup element is advantageously provided with a ring-shaped edge 8 firmly secured to a corresponding ring-shaped portion of said solid base 3 of the first cylindrical portion 1.

In essence, said cup element 6 is engaged securely above said first portion 1 due to the opposing actions between said elastic means 5 and the reaction force of said ring-shaped edge 8 against said solid base 3.

A useful accessory of the spacer according to the invention is shown in FIGS. 9A, 9B, 9C, 10A, 10B, 10C, 11A, and 11B; this accessory aims to overcome the drawback of having to remove and store the spacer of the invention somewhere after it has been used, and to find and reinstall it afterward; these work steps can be eliminated completely by providing the spacer of the invention with a useful accessory making it quick and easy to remove the spacer from its working portion while the stamping machine is operating, but which keeps it connected to a part of the machine, be it the die or column, so that it can be reinstalled in its working position (when the machine is stopped) in an equally quick and easy manner.

To that end, a holding element is made and equipped:

-   -   with a first ring-shaped part 10 which can be secured firmly to         the outer cylindrical surface of said second cylindrical portion         2,     -   and a second part 11 designed so as to be secured against one of         said elements, be it the die or column, and into which said         first ring-shaped part 10 is engaged by rotation, preferably by         means of hinge 12 on an outer edge of said first ring-shaped         part 10.

Said second part 11 can in turn be equipped with attachment devices, preferably through-elements such as bolts, pins, or the like, not explicitly shown, which are inserted into appropriate through-holes 13 made in said second part 11, which may be made directly from a simple plate.

The operation of said attachment element consists primarily in:

-   -   placing said second part 11 on an edge of the die or column, as         shown schematically in FIGS. 10A and 10B, by means of said bolts         which pass through said through-holes 13 and which engage with         the die (or column),     -   and then, while making the first ring-shaped part 11 rotate on         said hinge 12, said first ring-shaped part is put in the desired         position so that the spacer of the invention is placed in the         working position, then alternatively:     -   inserted between the die and column, as shown symbolically in         FIG. 10A,     -   or removed from said working position by rotating hinge 12 180°         when the corresponding stamping machine is working.

In addition, said first ring-shaped part 10 is advantageously made like a flexible jaw so that it can adapt to and clamp to different sized spacers and lock onto them so as not to be removable; consequently, said first ring-shaped part 10 is made like a ring that is radially open by a transverse slot 15, which can be clamped by a suitable clamping device, typically a bolt 14, by known design and construction features.

Lastly, in order for said spacer to be made in an economically sustainable and industrially practical way, it is appropriate for the first portion and the second portion to be made as a single piece by means of a known thermoplastic-material injection process.

The preferred plastic material has been determined advantageously to include semi-crystalline polyamides or polymers.

In particular, in order to ensure that the thermoplastic material has a very high hardness and strength, it is particularly useful to add a fiberglass reinforcement component of at least 20% by weight to said plastic material.

It has been found that a perfectly suitable material for this purpose is available on the market under the trade name “Greenamid PA6 (GF30).” 

1. A spacing holder for dies or stamping machines which can constitute a means of spacing apart two opposing parts of said die, wherein it includes: a first cylindrical portion equipped with: an inside recess open to the outside at one base, with the opposite base thereof being solid, a second cylindrical portion, at least partially solid, attached securely to and outside said solid base, with an outside diameter that is less than the outside diamter of said first portion; wherein said first and second cylindrical portions and said inside recess are coaxial.
 2. A die or stamping machine holder according to claim 1, wherein it includes: an elastic damping means attached inside said inside recess and protruding therefrom, a cup element placed outside and above said elastic means and outside said first cylindrical portion.
 3. A die or stamping machine holder according to claim 2, wherein said cup element is provided with a ring-shaped edge attached securely to a corresponding ring-shaped portion of said solid base of said first cylindrical portion.
 4. A die or stamping machine holder according to claim 1, wherein it includes a grasping element equipped: with a first ring-shaped part which can be secured firmly to the outside of said second cylindrical portion, and a second part attached by rotating means to an outer edge of said first ring-shaped part.
 5. A die or stamping machine holder according to claim 4, wherein said means of rotation includes a hinge.
 6. A die or stamping machine holder according to claim 4, wherein said second part is equipped with grasping devices.
 7. A die or stamping machine holder according to claim 4, wherein said first ring-shaped part is equipped with a device for clamping or locking to the outer surface of said second cylindrical portion.
 8. A die or stamping machine holder according to claim 1, wherein said first cylindrical portion and said second cylindrical portion are made as a single part by means of a thermoplastic-material injection process.
 9. A die or stamping machine holder according to claim 9, wherein said thermoplastic material includes semi-crystalline polyamides or polymers.
 10. A die or stamping machine holder according to claim claim 9, wherein said material includes fiberglass reinforcement of at least 20% by weight. 